Conveying devices, such as those which are used for moving objects between different stations in a factory, usually comprise a conveying track in the form of a belt or a chain. The conveying tracks can be sunken in a trench with vertical side surfaces. Alternatively, they can be located on the horizontal upper surfaces of the trench or arranged in some other way.
The objects to be conveyed are arranged slidably in relation to the conveying tracks, either directly or via bearing means, what are known as pallets.
When a pallet is conveyed along the conveying device and arrives at a work station, it is stopped by a stop. Performance of the work operation on the load on the pallet can then begin.
When it is difficult to coordinate the work so that every pallet spends the same length of time in each work station, there is a risk of a queue of pallets being formed before a work station. It is inappropriate for the braking of a pallet which takes place before a work station to take place solely by virtue of the pallet colliding with the pallet in front. If work is being carried out on the load on the pallet in front, there is a risk of the load being damaged.
Attempts have been made to solve this problem by providing the pallets with rubber shock absorbers.
It has nevertheless been found that this does not provide the necessary shock absorption, for which reason the problem remains to be solved in an effective manner.
U.S. Pat. No. 4,605,121 describes a braking device for braking objects on a conveying track which seeks to solve the abovementioned problem. The braking device is arranged in the form of elastic elements positioned between the objects or pallets they are to brake. Under the pressure which arises when a pallet behind is braked against the braking device, the latter is compressed in the conveying direction. This results in the device expanding transversely to the conveying direction. When this expansion takes place, the braking device will, on account of its dimensioning, bear against the vertical side surfaces of the conveying track. Owing to the friction which then arises between the braking device and the side surfaces, the pallet will be braked. However, the construction above affords limited possibilities for varying the braking effect. There is therefore a need for a braking device which can be varied to a greater extent with regard to the braking effect.